115Plant Fiber–Based Composites
the ber surface, the hydrogen bond breaks and hydroxyl groups form new hydrogen
bonds with water molecules. The cross section of the ber becomes the main access
to the penetrating water. As a result, when hydrophilic cellulosic ber is reinforced
with hydrophobic resin, swelling within the matrix occurs. This causes weak bond-
ing between ber and matrix, dimensional instability, matrix cracking, and poor
mechanical properties of the composites (Vaxman et al. 2004).
Therefore, the removal of moisture from bers is an essential step before the
preparation of composites. The moisture absorption of natural bers can be reduced
by different chemical treatments such as alkali treatment, silane treatment, acetyla